Squamous cell carcinoma as a cause of dyspnea and blindness in a horse.

An 8-year-old horse was investigated for a chronic nasal discharge and blockage, which was discovered to be caused by a cancerous mass in the sinuses, among other locations. Despite surgery to reduce the size of the mass and improve the horse’s breathing, the cancer led to acute blindness a few weeks post-surgery due to pressure on the optic tracts.

Background

• The study focuses on a case where an 8-year-old Quarter Horse mare presented with chronic nasal discharge and obstruction in both nasal passages.
• Upon examination, a solid mass was identified in the maxillary sinuses, soft palate, nasal, and pharyngeal cavities.

Surgical interventions and Diagnosis

• The researchers opted for palliative surgery, which aims to relieve symptoms rather than to cure the disease, in order to debulk the lesion and facilitate nasal airflow.
• Biopsies taken during the surgery led to the diagnosis of Squamous cell carcinoma, which is a common type of skin cancer.

Post-surgical Complications

• Approximately 7-8 weeks after the surgery, the mare rapidly lost its sight. Ophthalmologic examination revealed that this was central origin blindness, along with active retinitis, which is inflammation of the retina.
• The carcinoma had reobstructed the nasal passages, demonstrating the aggressive nature of this type of cancer and its tendency to recur quickly.

Link between the Carcinoma and Blindness

• The expanding tumor exerted pressure on and deformed the ethmoid and sphenoid bones, which are located close to the eyes. These changes resulted in compression of the optic tracts, leading to the horse’s blindness.
• It’s significant to note that despite the considerable impact of the tumor, it hadn’t invaded the bone itself.

The study provides valuable insight into the aggressive nature of squamous cell carcinoma in horses and its potential to cause severe complications such as blindness. It also underscores the importance of early detection and intervention in managing such conditions effectively.